Chilwa Minerals (ASX:CHW) has intersected a laterally extensive, free-dig saprolite horizon during reconnaissance drilling at its Mpyupyu West heavy mineral sands prospect in Malawi.
The company has completed 60 sonic holes for 551m across the 17km² target, representing 22% of a planned 268-hole first-phase program.
Chilwa notes the drilling has identified a consistent sequence of mineralised sand, silty sand, sandy clay, and deeply weathered saprolite from surface. The interpreted mineralised horizon averages 7.3m thick and reaches up to 12m.
The drilling indicates Mpyupyu West is an in situ, residually concentrated saprolite-hosted system, differing from the shallow lacustrine deposits elsewhere on its licences.
Managing Director Cadell Buss says the results have improved the company’s understanding of the prospect’s geology.
“We are intersecting soft, free-dig saprolite from surface, hole after hole, across a target area of more than 17km²,” Buss says.
However, Chilwa has not reported drilling assays. Total heavy mineral content will be determined through laboratory sink-float analysis once sample export permitting is complete, with initial results expected in October 2026.
Portable X-ray fluorescence analysis is being conducted on core at 0.5m intervals to support geological domaining. The company says it has also completed 153 additional surface samples, taking the total to 227, with visual heavy-mineral estimates ranging from 0% to 20%.
Both sonic rigs are operating at Mpyupyu West, with the first-phase program scheduled for completion in late September. The company notes results will guide a second-phase resource-definition program on a 100m by 100m grid.
Mpyupyu West adjoins the existing 109.6 million tonnes Mpyupyu mineral resource. Chilwa says it is also advancing a Scoping Study covering its heavy mineral sands deposits around Lake Chilwa, targeted for completion during the September quarter.
Write to France Pinzon at Mining.com.au
Images: Chilwa Minerals
